/*
 * Copyright 2012-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.springcloud.gray.bean.properties.source;

import java.util.List;
import java.util.stream.Stream;

import org.springframework.util.CollectionUtils;

/**
 * A {@link IterableConfigurationPropertySource} supporting name aliases.
 *
 * @author Phillip Webb
 * @author Madhura Bhave
 */
class AliasedIterableConfigurationPropertySource
        extends AliasedConfigurationPropertySource
        implements IterableConfigurationPropertySource {

    AliasedIterableConfigurationPropertySource(IterableConfigurationPropertySource source,
                                               ConfigurationPropertyNameAliases aliases) {
        super(source, aliases);
    }

    @Override
    public Stream<ConfigurationPropertyName> stream() {
        return getSource().stream().flatMap(this::addAliases);
    }

    private Stream<ConfigurationPropertyName> addAliases(ConfigurationPropertyName name) {
        Stream<ConfigurationPropertyName> names = Stream.of(name);
        List<ConfigurationPropertyName> aliases = getAliases().getAliases(name);
        if (CollectionUtils.isEmpty(aliases)) {
            return names;
        }
        return Stream.concat(names, aliases.stream());
    }

    @Override
    protected IterableConfigurationPropertySource getSource() {
        return (IterableConfigurationPropertySource) super.getSource();
    }

}
